Fix deprecated six imports for CI compliance

Replace deprecated ansible.module_utils.six imports with Python 3
standard library equivalents to pass pylint sanity checks.

plugins/action/synchronize.py:
- ansible.module_utils.six.string_types → str
- ansible.module_utils.six.moves.shlex_quote → shlex.quote

plugins/modules/synchronize.py:
- ansible.module_utils.six.moves.shlex_quote → shlex.quote

plugins/modules/mount.py:
- ansible.module_utils.six.iteritems → dict.items()

plugins/action/synchronize.py

@@ -19,10 +19,9 @@ __metaclass__ = type
 
 import os.path
 from collections.abc import MutableSequence
+from shlex import quote as shlex_quote
 
 from ansible import constants as C
-from ansible.module_utils.six import string_types
-from ansible.module_utils.six.moves import shlex_quote
 from ansible.module_utils.common.text.converters import to_text
 from ansible.module_utils.parsing.convert_bool import boolean
 from ansible.plugins.action import ActionBase
@@ -417,7 +416,7 @@ class ActionModule(ActionBase):
             # Replicate what we do in the module argumentspec handling for lists
             if not isinstance(_tmp_args.get('rsync_opts'), MutableSequence):
                 tmp_rsync_opts = _tmp_args.get('rsync_opts', [])
-                if isinstance(tmp_rsync_opts, string_types):
+                if isinstance(tmp_rsync_opts, str):
                     tmp_rsync_opts = tmp_rsync_opts.split(',')
                 elif isinstance(tmp_rsync_opts, (int, float)):
                     tmp_rsync_opts = [to_text(tmp_rsync_opts)]

plugins/modules/mount.py

@@ -225,7 +225,6 @@ import platform
 
 from ansible.module_utils.basic import AnsibleModule
 from ansible_collections.ansible.posix.plugins.module_utils.mount import ismount
-from ansible.module_utils.six import iteritems
 from ansible.module_utils.common.text.converters import to_bytes, to_native
 from ansible.module_utils.parsing.convert_bool import boolean
 
@@ -279,7 +278,7 @@ def _set_mount_save_old(module, args):
     old_lines = []
     exists = False
     changed = False
-    escaped_args = dict([(k, _escape_fstab(v)) for k, v in iteritems(args)])
+    escaped_args = dict([(k, _escape_fstab(v)) for k, v in args.items()])
     new_line = '%(src)s %(name)s %(fstype)s %(opts)s %(dump)s %(passno)s\n'
 
     if platform.system() == 'SunOS':

plugins/modules/synchronize.py

@@ -367,9 +367,16 @@ EXAMPLES = r'''
 import os
 import errno
 
+# TODO(Python2): shlex.quote was added in Python 3.3. This module may run on
+# target hosts with Python 2.7 (e.g., older RHEL systems in CI integration tests).
+# Remove the try/except fallback to pipes.quote when Python 2 support is dropped.
+try:
+    from shlex import quote as shlex_quote
+except ImportError:
+    from pipes import quote as shlex_quote
+
 from ansible.module_utils.basic import AnsibleModule
 from ansible.module_utils.common.text.converters import to_bytes, to_native
-from ansible.module_utils.six.moves import shlex_quote
 
 
 client_addr = None